Vb.net 单击保存按钮后如何显示消息框错误/成功
我一直在网上搜索解决方案,但由于某种原因似乎找不到 我想在单击“保存”按钮时显示一个消息框,显示“保存成功”或错误消息 以下是迄今为止按钮的代码:Vb.net 单击保存按钮后如何显示消息框错误/成功,vb.net,listbox,save,messagebox,Vb.net,Listbox,Save,Messagebox,我一直在网上搜索解决方案,但由于某种原因似乎找不到 我想在单击“保存”按钮时显示一个消息框,显示“保存成功”或错误消息 以下是迄今为止按钮的代码: Private Sub Button3_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnSaveKeywords.Click IO.Directory.CreateDirectory("C:\TESTING") Dim w As
Private Sub Button3_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnSaveKeywords.Click
IO.Directory.CreateDirectory("C:\TESTING")
Dim w As New IO.StreamWriter("C:\TESTING\Keywords.txt")
Dim i As Integer
For i = 0 To ListBox1.Items.Count - 1
w.WriteLine(ListBox1.Items.Item(i))
Next
w.Close()
End Sub
任何帮助都将不胜感激。谢谢。您可以使用Try-Catch来检测程序中的错误,因此如果出现错误,它将发送错误消息。例如:
Private Sub Button3_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnSaveKeywords.Click
Try
IO.Directory.CreateDirectory("C:\TESTING")
Dim w As New IO.StreamWriter("C:\TESTING\Keywords.txt")
Dim i As Integer
For i = 0 To ListBox1.Items.Count - 1
w.WriteLine(ListBox1.Items.Item(i))
Next
MessageBox.Show("Saved Successfully")
Catch ex as exception
Messagebox.show("Error when saving. " & ex.tostring, "Data error ")
Finally
w.Close()
End Try
End Sub
即使保存成功或出现错误,finally也将始终关闭streamwriter流
另一方面,我会以这种方式亲自写信给文件
Dim FileLocation as string = "C:\TESTING\Keywords.txt"
System.IO.File.WriteAllLines(FileLocation, ListBox1.ToArray, System.Text.Encoding.Default)
(上面一行未经测试,因此ListBox1.ToArray可能无法工作,但如果无法工作,则很容易修复)理想情况下,单击按钮时应包含尽可能少的代码,并调用包含大部分代码的子函数或函数,如下图所示,但这不是问题所在 您应该尽可能多地检查代码中的错误-在您的情况下,检查目录是否已经存在
Private Sub Button3_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnSaveKeywords.Click
SaveFile("C:\TESTING\Keywords.txt")
End Sub
Private Sub SaveFile(fileName As String)
If Not Directory.Exists(Path.GetDirectoryName(fileName)) Then
IO.Directory.CreateDirectory(path.GetDirectoryName(fileName))
End If
Dim w As New IO.StreamWriter()
Dim i As Integer
Try
For i = 0 To ListBox1.Items.Count - 1
w.WriteLine(ListBox1.Items.Item(i))
Next
Catch ex As Exception
MessageBox.Show("Error saving File: " & fileName & vbCrLf & "Exception Details" & vbCrLf & ex)
Finally
w.Close()
End Sub
步骤1:实现一种检测问题的方法-添加一个Try-Catch;步骤2:处置StreamWriter;步骤3:显示catch中设置的错误消息,或者您怀疑的默认“保存成功”,ListBox1.ToArray将不会编译。但是,
ListBox1.Items.OfType(Of String).ToArray
将从列表框中的项创建一个字符串数组WriteAllines
对IEnumerable(字符串的)
很满意,因此出于您的目的,您可以使用ListBox1.Items.Of(字符串的)